高压氮气冷却特性研究

Study on Cooling Characters of High Pressure Nitrogen

以1.2 MPa IPSEN高压气淬炉为研究对象,通过设计与ISO9950相同大小的钢探头,利用Keithley2700作为数据采集系统,研究了氮气在不同压力下以及不同种类钢探头的冷却速度。结果表明:高压气体冷却过程中最大冷速位置出现在700℃附近,压力为1.2 MPa时冷速最大为15.4℃/s,远小于N32最大冷却速度;D6AC探头在0.8 MPa以上可以淬透,但40Cr和45钢探头即使压力达到1.2 MPa也无法淬透;高压气淬适合于临界冷却温度接近于700℃左右淬透性较好的钢种。

1.2 MPa high pressure furnace of IPSEN was studied. The cooling rates of different materials at different pressures were measured by designing probe which is the same as the ISO9950 probe. And experimental data were collected by keithley 2700 meter. The results show that the max cooling rate appears at about 700℃ and the max cooling rate is 15.4 ℃/s at 1.2 MPa. When the pressure is above 0.8 MPa the probe of D6AC can realize full quenching. But the probe of 40Cr and 45 steel can not realize full quenching although the gas pressure reaches 1.2 MPa. So quenching by high pressure fits for alloyed steels with better hardenability, whose critical cooling temperature is about 700 ℃.